The present invention relates in general to electrophotographic imaging members and processes for fabricating the members.
A common technique for manufacturing xeroradiographic photoreceptor plates involves vacuum deposition of an amorphous selenium alloy layer having a thickness of about 150 microns onto an aluminum substrate at about 75.degree. C. (167.degree. F.). The deposited selenium alloy layer is usually free of crystalline selenium. These xeroradiographic plates may be overcoated with a protective coating.
Small x-ray selenium photoreceptor plates normally comprise an aluminum substrate. The aluminum substrate is desirable to achieve a selenium-substrate interface which will yield a low dark decay rate and minimal defect level. The aluminum substrate is usually mounted with double backed adhesive tape onto a support member in a vacuum coater.
For dental plates, a large number of plates, usually 216 plates, are vacuum coated at one time. A double sided adhesive tape is manually applied to the back of each of the 216 plates. Each of these taped plates is thereafter applied onto a support member. The support member bearing the 216 plates is inserted into a vacuum chamber for deposition of selenium onto the exposed surface of each substrate. Prior to deposition of the selenium onto the substrate, a vacuum is imposed on the vacuum chamber to out gas undesirable gasses and vapor contained in the adhesive tape. The 216 plates are thereafter removed from the vacuum coater and an overcoating of protective material is applied to each plate. The tape is thereafter removed from each of the 216 plates and each plate is cleaned to remove any residual adhesive. Each of the 216 plates are thereafter individually glued to separate plastic bases and individually tested for defects. Any defects found during testing requires discarding of the plate and plastic base. Acceptable plates in the plastic bases are subsequently inserted into light tight packages for insertion into a patient's mouth during x-ray exposure.
This dental plate fabrication process is laborious and extremely time consuming. It is apparent that considerable coating equipment down time occurs due to cleaning the plate holders, applying 216 pieces of double sided sticky tape, mounting 216 plates on the tape pieces, outgassing the tape, vacuum coating the plates, removing the plates and repeating the process steps for applying a protective overcoating to each plate. Moreover, the cost of the plastic base and the time spent for gluing are lost for those plates are rejected after testing. Moreover, the discarding of defective plates includes loss of the plastic bases and time to glue the plates to the plastic bases.